Dealing with Artifacts in The Render?
The problem here is all about that evil word good modelers often use:
Topology
Here are some ways to improve this:

Do some research on good mesh topology techniques and USE THEM

Use smooth shading

Your model looks far to detailed right now (as far as vertex count)...try removing some of the edge loops, and adding a subdivision surface modifier

A lot of your trouble is coming from vertices that are actually inside the mesh...try switching to wireframe view to pull these out (if you cleanup your mesh and use a subsurf, this will be much easier to do

Finally, like Anson said, you should be checking your normals often...hit Ctrl + N


The technique of modeling with a subsurf modifier is huge!